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Related papers: Thermoacoustic tomography arising in brain imaging

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In this work, the inverse problem of quantitative thermoacoustic tomography is studied. In quantitative thermoacoustic tomography, dielectric parameters of an imaged target are estimated from an absorbed energy density induced by an…

Computational Physics · Physics 2024-10-10 Teemu Sahlström , Timo Lähivaara , Tanja Tarvainen

This is the manuscript of the chapter for a planned Handbook of Mathematical Methods in Imaging that surveys the mathematical models, problems, and algorithms of the Thermoacoustic (TAT) and Photoacoustic (PAT) Tomography. TAT and PAT…

Analysis of PDEs · Mathematics 2011-10-04 Peter Kuchment , Leonid Kunyansky

Photoacoustic fluctuation imaging, which exploits randomness in photoacoustic generation, provides enhanced images in terms of resolution and visibility, as compared to conventional photoacoustic images. While a few experimental…

Optics · Physics 2020-11-19 Sergey Vilov , Guillaume Godefroy , Bastien Arnal , Emmanuel Bossy

In this work, it is shown that image reconstruction methods from ultrasonic imaging can be employed for thermographic signals. Before using these imaging methods, a virtual signal is calculated by applying a local transformation to the…

Data Analysis, Statistics and Probability · Physics 2017-03-16 Peter Burgholzer , Michael Thor , Jürgen Gruber , Günther Mayr

We present a self-consistent theory for sound propagation in a simple model of a disordered solid. The solid is modeled as a collection of randomly distributed particles connected by harmonic springs with strengths that depend on the…

Disordered Systems and Neural Networks · Physics 2024-12-20 Grzegorz Szamel

Photoacoustic tomography is a contrast agent-free imaging technique capable of visualizing blood vessels and tumor-associated vascularization in breast tissue. While sophisticated breast imaging systems have been recently developed, there…

Thermoacoustic instabilities observed in turbulent combustion systems have disastrous consequences and are notoriously challenging to model, predict and control. Here, we introduce a mean-field model of thermoacoustic transitions, where the…

A method for photoacoustic tomography is presented that uses circular integrals of the acoustic wave for the reconstruction of a three-dimensional image. Image reconstruction is a two-step process: In the first step data from a stack of…

Numerical Analysis · Mathematics 2009-12-06 G. Zangerl , O. Scherzer , M. Haltmeier

Photoacoustic imaging is an emerging technology based on the photoacoustic effect that has developed rapidly in recent years. It combines the high contrast of optical imaging and the high penetration and high resolution of acoustic imaging.…

Speed of sound is a key parameter for the compressibility effects in multiphase flow. We present a new approach to do direct numerical simulations on the speed of sound in compressible two-phase flow, based on the stratified multiphase flow…

Fluid Dynamics · Physics 2018-03-22 Kai Fu , Xiao-Long Deng , Lingjie Jiang

In this article, we revisit iterative methods for solving the inverse problem of photoacoustic tomography in free space. Recently, there have been interesting developments on explicit formulations of the adjoint operator, demonstrating that…

Analysis of PDEs · Mathematics 2017-05-16 Markus Haltmeier , Linh V. Nguyen

In this paper we derive time reversal imaging functionals for two strongly causal acoustic attenuation models, which have been proposed recently. The time reversal techniques are based on recently proposed ideas of Ammari et al for the…

Analysis of PDEs · Mathematics 2015-06-12 Konstantinos Kalimeris , Otmar Scherzer

Acoustic holographic lenses, also known as acoustic holograms, can change the phase of a transmitted wavefront in order to shape and construct complex ultrasound pressure fields, often for focusing the acoustic energy on a target region.…

We investigate the speed of sound in nuclear matter at finite temperature and density~(chemical potential) in the nonlinear Walecka model. The numerical results suggest that the behaviors of sound speed are closely related to the the…

Nuclear Theory · Physics 2023-01-13 Wei-bo He , Guo-yun Shao , Chong-long Xie

The speed of sound refers to the rate at which information travels from one point to another. It is a positive quantity and bounded by causality. It is defined as the rate of change of pressure with respect to the system's density. In this…

High Energy Astrophysical Phenomena · Physics 2026-01-19 Anshuman Verma , Asim Kumar Saha , Ritam Mallick

Photoacoustic image reconstruction often assumes that the restriction of the acoustic pressure on the detection surface is given. However, commonly used detectors often have a certain directivity and frequency dependence, in which case the…

Numerical Analysis · Mathematics 2020-01-08 Gerhard Zangerl , Sunghwan Moon , Markus Haltmeier

The spectrum of the interior transmission problem is related to the unique determination of the acoustic properties of a body in thermoacoustic imaging. Under a non-trapping hypothesis, we show that sparsity of the interior transmission…

Analysis of PDEs · Mathematics 2015-06-16 David Finch , Kyle S. Hickmann

In this paper we consider the inverse problem of vibro-acoustography, a technique for enhancing ultrasound imaging by making use of nonlinear effects. It amounts to determining two spatially variable coefficients in a system of PDEs…

Numerical Analysis · Mathematics 2023-03-31 Barbara Kaltenbacher ans teresa Rauscher

Sound speed heterogeneities can create aberrations in B-mode ultrasound images by inducing tissue-dependent delays and diffractive effects that conventional beamforming does not incorporate. By using the Fourier split-step method to…

Medical Physics · Physics 2026-05-01 Rehman Ali , Trevor M. Mitcham , Marvin M. Doyley , Nebojsa Duric , Jeremy J. Dahl

We exploit a generic instability in the integration of steady, sonic, near-isothermal flows to find the complete transition diagram for recombination fronts (for a model system of equations). The instability requires the integration of the…

Astrophysics · Physics 2015-06-24 R. J. R. Williams , J. E. Dyson